I think our difference in opinion stems from how we interpret the concept of the Quantum Ogre;
I see it as a narrative slot-filler, a sequential step in the adventure, not as a product of agency but rather of time. The ogre is inevitable, but the high crime of "agency theft" is negated by way of not having given player's agency over this one specific ogre in the first place. They'll have their chances to make choices and affect outcome, it's just that the concept of the quantum ogre is immune to such power by the nature of its being, and so they won't be able to affect it.
The game is whatever interface the players experience - so long as it stays on your side of the screen, for all intents and purposes it doesn't exist. Quantum ogres live and breathe on the DM's side of the screen, and so likewise should be considered innocent of agency-theft by virtue of its "technical" non-existence.
I can see and appreciate some of the alternative viewpoints:
- citing the quantum ogre as a teleporting, omniscient threat or annoyance. An unfair situation and abuse of DM fiat.
- diminished the sense of freedom/control/agency felt by the party. Against the spirit of the game's free-form/randomized nature.
-fostering a DM vs. Player mentality (adversarial DMing)
A lot of these claims can be retorted with "git gud, DM" (in a nutshell). In particular, mitigating adversarial DMing is a quick fix on the DMs part (since they represent half of the problem - learning how to dial back on the throttle and whatnot), and any perceived agency violation can be smoothed over with narrative technique, improvisation, and/or agency alternatives (i.e. other situations involving agency taking place at the same time - if the quantum ogre exists regardless of agency, the alternative becomes "do you approach the ogre from up on those rocks, or from the safety of the treeline?").
The view of the quantum ogre as railroading is especially interesting, because it flies counter to my personal belief that the game, collaboratively, exists solely as what comes from mouths and goes to ears, and nothing more. Railroading is a problem of pre-cognition about the path ahead, and knowing what actions the party will take regardless of their choices. At worst wat we have is more of a "ride in the fog", in that the players may or may not be on rails, but they can't see beyond a foot in front of their own faces. Are they turning left or right ahead? Who knows... too much fog. Well the DM knows - he doesn't see any fog, and has a bird's eye view. But like all things DM-side, none of it exists until it's communicated to the players, so it becomes irrelevant.